Addressing an audience that included BBC presenter Clare Balding and her partner, the former newsreader Alice Arnold, Mr Cameron boasted that Britain was now ‘the best place to be gay, lesbian or transgender anywhere in Europe’ But he risked controversy by suggesting that his ministers should now fan out across the globe to spread gay marriage around the world.

‘I’m personally proud of this,’ he said. ‘I think it’s a really good step. I’ve told the Bill team I’m now going to reassign them because, of course, all over the world people would have been watching this and we’ve set something of an example of how to pass good legislation in good time.

‘Many countries are going to want to copy this. I talk about how we’ve got to export more, so I’m going to export the Bill team.